It should be fast enough to handle double aggro easily and powerful enough to take down most everything in one shot. What it doesn't kill it should knock back since it gains charges so quick at rank 1. The advantage over Ice spear is much higher single target damage and not having to worry about drawing aggro from everything caught in your AoE. Mana usage should be way less than spear and it's going to be absolute hax on boss monsters.
Do fully charged bolts always cause knockback? It really isn't that strong, at least not enough for one-shotting in Hard Shadow Missions (by the looks of it, it would take maybe 3-7 non-crits).
It's clearly a replacement for CC+4 Firebolt with stellar damage, but it doesn't look like it can compete with Intermediate magic as far as quickly clearing groups of mobs goes (Shadow Wizard and Orb Room type situations).